Polyphenols of Edible Macroalgae: Estimation of In Vitro Bio-Accessibility and Cytotoxicity, Quantification by LC-MS/MS and Potential Utilization as an Antimicrobial and Functional Food Ingredient

Abstract

Macroalgae are a rich source of polyphenols, and their ingestion promotes various health benefits. However, information on factors contributing to health benefits such as antioxidants, antimicrobial properties, bioaccessibility, and cytotoxicity is less explored and often unavailable. Therefore, this study aims to investigate the above-mentioned parameters for the brown and green macroalgae Sargassum wightii and Ulva rigida, respectively, collected from the southeast coast of India. S. wightii exhibited higher antioxidant activity and moderate antimicrobial activity against major food pathogens in an agar well diffusion assay and in the broth microdilution method (MIC50 being <0.5 mg/mL for all microorganisms tested). Both macroalgae extracts exhibited significantly high bioaccessibility of polyphenols. To evaluate the safety of the extracts, in vitro cytotoxicity by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was carried out on the primary cells: mouse splenic lymphocytes. An almost complete decline in the cell viability was seen at considerably high concentration (50 mg/mL), expressing the reasonably high safety of the extracts. The extracts of both macroalgae were quantified for polyphenols, wherein fucoxanthin (9.27 ± 2.28 mg/kg DW) and phloroglucinol (17.96 ± 2.80 mg/kg DW) were found to be greater in the S. wightii apart from other phenolics, like gallic acid, quercetin, vanillin, and ferulic acid. The results signify the tremendous scope for the value addition of S. wightii through extraction and purification of polyphenols for its potential exploitation in functional foods and nutraceuticals or as an antimicrobial ingredient in active or smart packaging.

Naturally Occurring Functional Ingredient from Filamentous Thermophilic Cyanobacterium Leptolyngbya sp. KC45: Phytochemical Characterizations and Their Multiple Bioactivities

“…As time has progressed, the idea of food has evolved to include the possibility of avoiding a variety of nutrition-related disorders and enhancing both physical and mental health. The concept of “Let food be thy medicine and medicine be thy food”, first proposed by Hippocrates roughly 2500 years ago, is gaining popularity today as a result of the growing awareness of the importance of eating nutritiously [ 1 ]. According to the World Health Organization (WHO), especially in developed nations, dietary patterns and lifestyle behaviors are the primary modifiable risk factors that contribute to the development of certain chronic illnesses such as diabetes, hyperpigmentation, xerosis, and hypertension, among others [ 2 ].…”

“…Other natural sources, such as macroalgae, microalgae, and cyanobacteria, are employed as active ingredients in the nutraceutical, cosmetic, and pharmaceutical sectors, in addition to medicinal plants, which are commercially accessible for preventing different ailments. They have a high concentration of bioactive phytochemical substances, particularly pigments and phenolic compounds, both of which are known to be beneficial to human health [ 1 , 4 , 5 ]. Pigments, such as chlorophylls and carotenoids, are examples of hydrophobic pigments that are commonly present in biomass [ 6 ].…”

“…Phenolic compounds (polyphenols) are a diverse group of secondary bioactive substances that include the hydroxybenzoic acids (protocatechuic, p-hydroxybenzoic, and syringic), hydroxycinnamic acids (caffeic, p-coumaric, and ferulic), flavan-3-ols (catechin and epicatechin), flavonoids (catechin, epicatechin, quercetin, and apigenin), glycosides, and proanthocyanidins [ 5 ]. Because phytochemicals have antioxidant characteristics, and there is evidence that they participate in numerous biological processes, such as those that are cardioprotective, anti-inflammatory, anticarcinogenic, antibacterial, and antiviral [ 1 ], there is an increased interest in the study of phytochemicals.…”

“…Cyanobacteria can have different biofunctional potentials depending on factors such as the species, the season, the temperature, the environment, the salinity of the water, the quantity of sunshine, the harvesting time, and even the collecting region [ 5 ]. Additionally, variations in the concentration of a solvent as well as the polarity of the solvent play significant roles in the process of extracting phytochemical substances [ 1 ]. On the cyanobacterium, Leptolyngbya sp., that was chosen for this investigation, there is a paucity of information regarding an appropriate solvent and solvent and its concentration for the purpose of extracting bioactivities [ 18 , 19 ].…”

Paramylon and Other Bioactive Molecules in Micro and Macroalgae

“…The ecological function of phenolic compounds in microalgae has been barely investigated. Macroalgae such as Gracilaria , Palmaria palmata , Halimeda sp., Ecklonia cava , Sargassum wightii , and Himanthalia elongata have been studied [ 37 , 38 , 39 ]. Among the few phenolics already identified, there are bromophenols, flavonoids, catechins, and phlorotannins [ 6 , 40 ].…”